Water heater



Feb. 9, 1943.

H. s. MURPHY WATER HEATER 3 Sheets-Sheet l Filed July 5, 1940 Feb. 9,1943. H. s. MURPHY 2,310,253

WATER HEATER Filed July 5, 1940 3 Sheets-Sheet 2 l l l I l L l VEN-rol;

SHSheets-Sheet 3 H. s. MURPHY WATER'HEATER Filed July 5, 1940 INVENTOR ATTORNEYSz i Feb. 9, 1943.

Patented Feb. 9, 1943 WATER HEATER Harry S. Murphy, Bulalo, N. Y., assigner to Coreco, Inc., Buialo, N. Y., a corporation of New York Application .uly 5, 1940, Serial No. 344,093

1 Claim.

This invention relates to a water heater and more particularly to a Water heater operating in conjunction with a hot Water or steam boiler, such as is used in heating a home, to supply domestic hot water to the various water fixtures of the house as intermittently required.

One of the principal objects of the invention is to supply such domestic hot water at very low cost, the heat for heating the water being derived largely from the iiue gases of the boiler the heating value of which is normally wasted.

Another object of the invention is to provide such a domestic water heater of the so-called instantaneous type in which the domestic Water is heated during a single passage through the coils of a heat exchanger, and to provide such a domestic Water heater which will supply an adequate amount of hot water which can be in excess of the heating capacity of the burner or source of heat of the boiler itself.

Another object of the invention is to provide such a domestic Water heater deriving heat from.

the flue gases of the boiler in which the heat transfer is eifeoted through the medium of the boiler water and in which the heat transfer surfaces and connections with the boiler are such that when domestic water is not being Withdrawn a reverse ow of the boiler water through the heater is effected, this boiler water being heated by the flue gases thereby to add to the overall economy of the boiler itself.

Another object is to provide such a domestic water heater deriving heat from the flue gases of the boiler in which the heat transfer is effected through the medium of the boiler water in such manner that the entire body of boiler water in the boiler is circulated to heat the domestic water thereby to permit of heating a large quantity of domestic water with only a small drop in the temperature of the boiler Water.

Another purpose is to provide such a domestic hot water heater which contains no moving parts and is simple and inexpensive in construction and will stand up under conditions of severe and constant use without requiring cleaning or repairs or losing erlicienoy.

Another aim is to provide such a domestic hot water heater for use in conjunction with a boiler which is readily adapted for use in the summer time when the service of the boiler as a house heating unit is not required.

Another object is to provide such a low cost domestic hot water heater which can be used in conjunction with either a steam or het Water boiler.

Another aim is to provide such a domestic hot Water heater which is compact in construction and readily accessible and can be secured directly to the boiler itself.

In the accompanying drawings:

Fig. 1 is a vertical, transverse, sectional view through the hot water heater and through a part of the boiler to which the heater is attached, this section being taken on line I-I, Fig. 3.

Fig. 2 is a fragmentary, Vertical, transverse section, taken on line 2 2, Fig. 3.

Fig, 3 is a rear view of the heater, partially in section, and showing the rear plate thereof removed.

Fig. 4 is a longitudinal horizontal section, taken on line 4-1i, Fig. 1,

The domestic water heater forming the subject of my invention is shown as used in conjunction with a boiler I0 which can be used to supply hot water or steam in heating a house. The boiler can be of any usual construction and can be of the sectional or non-sectional type and is shown as having a top wall I I and a flat rear wall I2, the flue I3 of the` boiler being shown as extending horizontally through the body of Water I4 Within the boiler and through a flue opening in the rear wall I2 thereof.

The domestic water heater of the present nvention consists essentially of a primary heat exchanger heated by the flue gases of the boiler and through which the boiler water in the boiler circulates in a vertical direction by gravity and a secondary heat exchanger immersed in the boiler Water so flowing through the primary heat exchanger and through which the domestic water is passed.

The primary heat exchanger is indicated generally at 29 and is shown as comprising an upper header 2l having a horizontal top Wall 22, inner and outer vertical walls 23 and 24, vertical end walls 25 and 2S and a lower horizontal tube sheet 2l and a similarly shaped lower header 28 having an upper horizontal tube sheet 29, inner and outer vertical Walls 35 and 3 I, a vertical end wall 32 and a horizontal bottom wall 34. The tube sheets 21 and 29 are connected by a suitable number of spaced tubes 35 each of which is perferably provided with external horizontal iins 3S and the ends of the two headers are connected by walls 3l and 38 which forma horizontal passage 39 through which the gases from the flue i3 pass around the exterior of the finned tubes 35. For this purpose the end walls 3i and 38 of this passage 39 are shown as each provided with an inwardly projecting ear lo which are secured to the rear wall I2 of the boiler by screws 4I in such position that the passage 39 registers with the outlet of the ue I3. The upper and lower headers 2| and 28, nned tubes 35, end Walls 3'I and 38 and attaching ears 40 are preferably all made in the form of a single casting, as shown.

To circulate the water in the boiler I through the primary heat exchanger, each end of the inner wall 23 of the upper header 2I is connected to the rear wall I2 of the boiler by a. slip nipple 45, these slip nipples providing communication between the interior of the upper header and the interior of the boiler below the level of the body of water I4 within the boiler. Similarly the inner wall 39 of the lower header 28 is connected to the rear wall I2 of the boiler below the ue I3 by a slip nipple 46, this slip nipple being centrally located and being larger in size than the two upper slip nipples 45 and providing communication between the interior of the lower header land the interior of the boiler below its flue I3. It will therefore be seen that the water I4 from the boiler I9 is free to circulate vertically in either direction through the slip nipples 45, upper header 2 I, finned tubes 35, lower header 28 and slip nipple 46 and that in passing through the nned tubes 35, this boiler water will be heated by the flue gases passing over the exterior of these tubes.

The rear end of the iue passage 39 through the primary heat exchanger is shown as closed by a plate 50 which can be secured to the body of the heat exchanger in any suitable manner and is provided with an outlet 5I surrounded by a neck 52 to which a smoke pipe 53 can be secured in the usual manner, this smoke pipe leading to a stack (not shown).

The end of the lower header 28 opposite the end wall 32 is shown as left open, as indicated at 54, to receive the secondary heat exchanger. indicated generally at 55. For this purpose this end of the lower header 28 is provided around the opening 54 with a laterally extending flange to which the header 56 of the secondary heat exchanger can be secured by bolts or screws 51. This header 56 is shown as having an inlet 58 and an outlet 59 for the domestic hot water, the interior of this header being suitably divided to provide inlet and outlet chambers (not shown) which are connected by a series of serpentine tubes 60, these tubes extending into the boiler water contained in the lower header 28. It will therefore be seen that the domestic water drawn through the tubes 60 of the secondary heat exchanger 55 by opening the hot water valve of one of the fixtures in the house will be heated through heat derived from the boiler water circulating through the lower header 28 of the primary heat exchanger 29.

Assuming the boiler I0 to be fired and hence hot flue gases to be passing from the ue I3 through the passage 39 in heat exchanging relation with the nned tubes 35 therein, when one of the hot water valves is opened, domestic water passes from the inlet 58 of the secondary heat exchanger 55 through its serpentine tubes 60 and outlet 59. In so passing through these tubes 60, the domestic water is heated by the boiler water contained in the lower header 28 of the primary heat exchanger and this boiler water contained in this lower Vheader of the primary heat exchanger is cooled. Ihis cooled boiler Water therefore flows down by gravity out through the slip nipple 46 into the boiler I0. This causes a downow of the boiler Water in the finned tubes 35 and an inow of boiler Water from the boiler I 0 through the inlet nipples 45 and upper header 2| of the primary heat exchanger. In so flowing down the finned tubes 35, the boiler water is heated by the passing flue gases, this heat being in turn transferred to the domestic water passing through the serpentine tubes 69 of the secondary heat exchanger, the heat of the domestic water being thereby in large measure derived from the normally wasted flue gases escaping from the outlet of the boiler iiue.

In the event that the boiler is not being fired when the domestic Water is withdrawn through the secondary heat exchanger, as in the summer time, the cooling of the boiler water in the lower header 28 of the primary heat exchanger causes a downward circulation of the boiler Water through the primary heat exchanger and an upward circulation of boiler water through the boiler I D. When the temperature of the entire body of Water I4 in the boiler drops to the setting of the usual control instruments, such as an aquastat (not shown) the burner supplying heat to the boiler is put in operation to place the boiler and water heater under the operating conditions first assumed.

During the major periods in which domestic water is not being drawn through the secondary heat exchanger 55, a reverse or upward move ment of the boiler Water in the primary heat exchanger 20 takes place. Thus with no load on the secondary heat exchanger 55, the boiler water in the finned tubes 35 of the primary heat exchanger is heated by the passing flue gases and flows upwardly by gravity out through the upper header 2I and slip nipples 45 to the interior of the boiler Ill, this inducing a flow of boiler water from the boiler I5 through the lower slip nipple 46 into the lower header 28 of the primary heat exchanger 29. When domestic water is not being withdrawn, therefore, the heat of the flue gases passing through the primary heat exchanger is used to heat the water in the boiler I0, this added heat very greatly increasing the overall economy of the boiler as a house heating unit.

Since the boiler I 0 contains a large quantity of boiler water I4, it will be seen that the load imposed upon the system by the withdrawal of domestic hot water can exceed the capacity of the burner or source of heat of the boiler itself and still supply domestic hot water of uniform temperature. Thus, this load is imposed upon the burner of the boiler only through the medium of the hot boiler water I4, suihcient to absorb a temporary overload which otherwise would result in cooler water being supplied at the fixture from which the domestic hot water is being withdrawn.

From the foregoing it will be seen that the present invention provides a domestic Water heater of simple and inexpensive construction which when used in conjunction with a house heating water or steam boiler not only produces hot water at very low cost through the use of heat derived from the flue gases leaving the boiler, but also increases the economy of the boiler itself by effecting a reversal of the ow of the boiler water when domestic hot water is not being withdrawn so that the heat derived from the ilue gases leaving the boiler is added to the water in the boiler itself. It will also be seen that the heater is free from operating diiliculties and can be used winter and summer to supply large quantities of domestic hot water.

through said shell, means for conducting the ue gases from said boiler in contact with the external surface of said shell thereby to heat the boiler water contained therein, and a heat exchanger including a header secured to the exterior of said shell and tubes extending into said shell and immersed in the boiler water therein, said header and tubes of said heat exchanger being adapted to conduct the water to be heated in heat exchanging relation to the boiler water in said shell.

HARRY S. MURP-IY. 

